Wash and dry the rosemary thoroughly. Remove the needles and place them into the bowl of a food processor.
With the motor running add the oil slowly and process until plant fiber breaks up and purees smoothly.
Heat the mixture very gently for about 20 minutes. Strain thru a double layer of dampened cheesecloth or muslin.
Do not press on solids but allow oil to drip through slowly.
Store in an airtight glass container.